Question: Which of the following numbers is a factor of 148? ${4,5,8,9,13}$
By definition, a factor of a number will divide evenly into that number. We can start by dividing $148$ by each of our answer choices. $148 \div 4 = 37$ $148 \div 5 = 29\text{ R }3$ $148 \div 8 = 18\text{ R }4$ $148 \div 9 = 16\text{ R }4$ $148 \div 13 = 11\text{ R }5$ The only answer choice that divides into $148$ with no remainder is $4$ $ 37$ $4$ $148$ We can check our answer by looking at the prime factorization of both numbers. Notice that the prime factors of $4$ are contained within the prime factors of $148$ $148 = 2\times2\times37 4 = 2\times2$ Therefore the only factor of $148$ out of our choices is $4$. We can say that $148$ is divisible by $4$.